Rotating shaft seal



Sept. 16, 1952 'r. T. WOODSON ROTATING SHAFT SEAL Filed Oct. 25. 1949 n:ma 3 tw flw 3 V A 2X6 Patented Sept. 16, 1952 ROTATING SHAFT SEALThomasflfi- Woodson, Bridgeport,,- Conn,, assignor to General ElectricCompany, a corporation of I New York Application October 25,1949,-SerialNo. 123,448

.1 Claim.

This invention :relates to improved means :for

-:sealing :rotatingtshafts against passage .of fluids,

Rotating shaft :seals ordinarily embody pairs of relatively :rotatingelements maintained in resilient pressure engagement by means including.a fiexibleboot structure :carrying .one of the elements. Themeetingsurfaces of the elements are lapped to provide an :area contact which istight against passage of fluids. Usually one of the elements is-of arelatively soft material having inherent lubricity-40p example, carbon,leaded bronze and the like-because the. elements are in dryrubbingcontact. The broad objectives .of my invention .areaccomplished bymounting the boot on the rotating shaft .in an improved sealingrelationship therewith and by carrying the softer element at the distalvend of the boot. The softer sealing element is effectively suported bytheshaft and there is no relative rotation .therebetween to. acceleratethe wear .of the element. Spring .m'eans disposed within the "bootmaintains the necessary resilient contact between the rotatingandkstationary components of the seal. I have improved the sealingengagement between the boot and the shaft by molding a rigid ringconcentrically within an enlarged end. wall through which the shaftextends. The material of the boot-rubber for exampleds squeezed radiallybetween the shaft and the backing ring to maintaina leak-sealingrelation between the :shaftand the 'boot. The internal ring structureprovides an improved base for thespring means, and it stiffens the endwall of the boot so as to constitute the latter .a ,rigid neck by whichthe sealing assembly maybe handled. Assembly is 'facilitatedzandperformance life improved by crimping the end of the flexible boot overa projecting rim of the associated seal member. With due care andhandling the crimping step is equally adaptable to carbon seal elementsas well as less frangible materials such as leaded bronze and the like.

Other features and advantages of the invention will be apparent from thefollowing detailed description of a presently preferred embodiment readin connection with the acompanying drawing in which Fig. 1 is asectional elevation of a typical application of a sealing assemblyembodying the invention, and Fig. 2 is an exploded view of therespective parts, shown in half section.

My invention as shown in Fig. 1 is applied to an automatic washinmachine [of the type disclosed in my presentlypending application SerialNo. 551,096, :filed August "25, 1944, now Patent No. 2,527,238, for"Clutch Structure for Spinner Type Washing Machines and assigned to-theas signee 'of'this application, Such machines 'illelude a rotatablebasket within which the clothes are washed by the operation ofmechanical ;;a gi tating means and ,in which they are centrifugallydried by rapidly rotating the basket after the free water has beenremoved. The agitator is carried on the end of a shaft I extendingupwardly into the basket to above the normalwater line thereof. Thebasket itself is carried by atubular shaft ,2 to whicha hub portion 3 ofthe basket supporting structure is keyed. Mechanism for selectivelyoscillating the shaft 1 or rotating the shaft 2 is contained within a,housing 4 having a neck portion 5, housing I and neck portion 5constituting meansfor journaling shaft 2, i. e., a frame member onwhichshaft ,2 is jour'naled.

As is explained in my aforesaid application the agitator has a centraltubular post of substantially larger diameter than that of the shaft I.Incident to the operation of the machine the water rises .in the basketto overflow into the above-mentioned central post .of the agitatorprevent contamination of washing liquid.

My improved seal construction comprisesthe mutually cooperating elements6, 1 which are respectively the rotating and stationary portions of thestructure. Element 6 includes a thin walled, flexible, rubber boot 8having a thickened annular collar 9 within which is concentricallymolded or otherwise disposed a rigid liner having the respectivesubstantially vertical and horizontal wall portions 10, l l each beingconcentricwith the boot aperture. As is shown to better advantage inFig. 2 the boot 8 is molded with a concentric offset portion l2 whichrests upon an upper shoulder l3 of a nose piece 14 which may be ofcarbon, leaded bronze or other suitable metals. By a thin metal eyeletl5 the depending portion 12 of the boot may be crimped about the nosepiece to maintain a fluid-tight contact 3 therewith. Within the boot Iprovide a light coil spring I 6 which may seat within an annular grooveI! disposed within a seating part of collar 9, i. e., the projected areaof the liner wall I l, and bear against the surface of the nose piece.

The fixed element 1 embodies a resilient washer 18 which seats snuglywithin a suitably provided pocket in the neck 5 of the casing 4.Said'washer may, if desired, be cemented to the neck to insure a sealingcontact with the casing wall. The cooperating seal member comprises ametal or equivalent ring IQ of angular cross section so as to provide aflat upper bearing surface engageable by the bottom wall or matingsurface of the nose piece [4 and a side wall snugly engaging the sidewall of the washer l8. The respectively engaging surfaces of the nosepiece 14 and the ring l9 are carefully lapped so as to make an adequatearea contact sealing against the flow of-oil and water.

The wall arrangement o'f'the liner contributes importantly to themaintenance of an efiicient sealing relationship at the shaft and at thenose piece. It will be noted that wall I0 is disposed adjacent theradially outermost portion of the collar 9 andprovides a concentricouter wall of a buttressing structure which includes the contactingsurface of hub 3 and the liner wall ll. Within the rigid boundariesthusestablished the flexible material of the collar is radiallydistorted by the shaft 2, it being understood that the collar apertureis deliberately under-sized relative to the shaft diameter. Accordingly,the shaft is engaged by a relatively large volume of material underessentially radial elastic compression. The boot necessarily rotateswith the shaft, and such rotation is transmitted to the nose piece [4through the combined effort of the boot 8 and the spring 16. It will benoted that the spring receiving channel H is immediately beneath thewall it, therefore providing a firm seat for the spring. There is norelative rotation between the nose piece and the shaft and the diametersthereof may have a close operational clearance; for example, a radialclearance of from .003 to .007 inch. Because of the absence ofrelativerotation this clearance will essentially be retained during use.An important advantage deriving from the support or centralizing effectof shaft 2 with respect to the nose piece [4 is the maintenance of therelative positions of .the nose piece and the cooperating fixed sealingsurface I9 for effective tracking. Rotating seals soon develop a grooveat their mating surfaces which is of microscopic dimension butnevertheless important to provide exactly matching profiles. Latera1freedom of movement of the respective fixed and rotating elements allowsone piece to jump. the track or groove and destroy the sealing effect.The small .4 radial clearance maintained by the support of the nosepiece on the shaft 2 is within the elastic freedom of the fixedstructure 1 and the dangers of accidental separation of the tracksurfaces is substantially eliminated.

While there has been shown and described a particular embodiment of thisinvention, it will be obviousto those skilled in the art that variouschanges and. modifications can be made therein without departing fromthe invention and therefore it is aimed in the appended claim to coveral1 such changes and modifications as fall within the true spirit andscope of the invention.

What I claim as new and desire to secure by I Letters Patent of theUnited States is:

For use with a shaft and means for journaling said shaft, a fluid sealcomprising an annular member carried by said journaling means concentricabout said shaft, said annular member having a bearing surface normal tothe axis of said shaft, a boot disposed about said shaft and comprisingan elastic collar portion spaced along said shaft from said annularmember and a flexible portion extending from said collar portion alongsaid shaft toward said annular member, an annular rigid liner moldedwithin said collar portion and integral therewith, said rigid linerhaving a first wall portion parallel to the axis of said shaft and asecond wall portion extending transversely to the axis of said shaftfrom said first wall portion but circumferentially spaced from saidshaft, a first part of said collar portion being held in compressionbetween said shaft and said first wall portion and a second seating partof said collar portion being adjacent to and backed by said second wallportion, an annular nose piece concentric about said shaft and axiallymovable thereon, means for fastening said nose piece in sealed relationto said flexible portion, said nose piece havin a mating surfacethereon, and resilient means for urging said mating surface into sealingcontact with said bearing surface, said resilient means being disposedbetween said boot and said, shaft and bearing axially agaimt,saidseating part which is reinforced thereagainst by said second wallportion.

THOMAS T. WOODSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS 2,472,257 I v Matter June 7, 1949

